Some Sql

1. Add [new_colum] after [another_column]

   • Add one column

ALTER TABLE `table_name`

ADD COLUMN `new_colum_name` INT(11) -- type

AFTER id;

CREATE INDEX index_name ON `table_name` (`column_name`);

1. • Add multiple columns

ALTER TABLE `table_name`

ADD COLUMN `new_colum_name_1` INT(11) -- type,

ADD COLUMN `new_colum_name_2` INT(11) -- type,

.

..

...

ADD COLUMN `new_colum_name_n` INT(11) -- type

AFTER id;

CREATE INDEX index_name ON `table_name` (`column_name`);

2. Change column to NULL default

   • Command: ALTER TABLE `table_name` CHANGE `old_column` `new_column` columnType() DEFAULT NULL;  

   • Example: ALTER TABLE `customer` CHANGE `customer_id` `customer_id` INT(11) DEFAULT NULL;

3. Update

4. Reference

   • https://tableplus.com/blog/2018/08/mysql-how-to-modify-column-to-become-nullable.html#:~:text=From%20the%20table%20view%2C%20switch,commit%20changes%20to%20the%20server